Instrument Used for Measurement

Instrument used for measurement

Making measurement by usisng some instrument or other is inevitable in physic.Hence, ensuring that careful and accurate reading are obtained for any measurement is of utmost importance.Table below shows some most commonly used instrument for making measurement in physics experiments.

|Physical quantity |Instrument |
|Length |Meter rule |
|Thickness,diameter |Vernier callipers,micrometer screw gauge |
|Mass |Electronic balance,beam balance, spring balance |
|Time |Stop watch |
|Temperature |Thermometer |
|Volume |Measuring cyinder |
|Current |Ammeter |

Uncertainties,Accuracies and Error in measurements

When we take measurement there are always uncertainties in the values.For example the diameter of a pencil is 7.5mm if we use a ruler with mm scale.The rulercan measure up to the nearest 0.5mm.But if we use amicrometer screw gauge it is 7.55mm which measures up to the nearest 0.01mm. the difference between the two values is in their uncertainties.The measurement using the micrometer screw gauge is better because it has a smalle uncertaintily.it is said to be more accurate.Thus less uncertainty means more accuracy.

The accuracy of a value indicates how close it is to the true value, when we write our measurement as 7.55+/- 0.01mm we mean the value is between 7.54mm and 7.56mm the first number is the uncertainity of the measurement. The accuracy of a